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pheaney

Noise from o/s rear - differential ?

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My car has been developing  a  sound from the rear which is getting worse. When taking off steadily  I get a rapid rapid hammering come graunching  from the rear o/s. Lapping round the local min-roundabout a few times slowly the noise is persistent .Starting up my drive which is on an upward slope brings the noise to the extreme.

I can also produce the noise with the handbrake on hard and the rear bobbing - so the rear wheels aren't rotating.

In general running about and at speed there is no sign of a problem. Managed to do 300 miles this Sunday gone  but it was getting worse during the day particularly hill starts.

Looking under the car I can see a lot of oil has escaped from the front seal of the differential.  Everything seems to rotate smoothly when not under load, the only thing I can spot 

rotating by hand is a bit of a knock on the o/s spline before it takes up drive.

I thought it might be a U/J  or a spline problem but I  guess at the moment something broken  inside the differential -  does that seem the most reasonable diagnosis ? 

Thanks for any ideas.

IMG_9800.JPG

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Drive shaft universal joint (s) Or diff mounts?

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12 hours ago, pheaney said:

I can also produce the noise with the handbrake on hard and the rear bobbing - so the rear wheels aren't rotating.

 

That would seem to exclude a diff problem; sounds to me like a UJ breaking up as they will move slightly when you compress the rear suspension with the car stationary. From what you've said, there may also be problems with the half shaft splines, these can wear significantly over time, especially if the rubber gaiters have split or been neglected. Sounds like a rear end strip down & rebuild might be on the cards, this will also give the opportunity to check out the diff. The original front oil seal was leather & I could never get these to seal without weeping (& yes they were soaked in oil for a couple of days before fitting), I eventually gave up & fitted a modern rubber lip seal - no more oil leaks.

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22 hours ago, Richard Crawley said:

That would seem to exclude a diff problem; sounds to me like a UJ breaking up as they will move slightly when you compress the rear suspension with the car stationary. From what you've said, there may also be problems with the half shaft splines, these can wear significantly over time, especially if the rubber gaiters have split or been neglected. Sounds like a rear end strip down & rebuild might be on the cards, this will also give the opportunity to check out the diff. The original front oil seal was leather & I could never get these to seal without weeping (& yes they were soaked in oil for a couple of days before fitting), I eventually gave up & fitted a modern rubber lip seal - no more oil leaks.

Thanks for the advice Richard that certainly makes sense regarding the UJ being the most likely culprit. All the gaiters underneath look fine so hopefully half shafts are ok.

I have a spare UJ so I will focus on replacing that and see how it goes.

Regarding the recommendation on the oil seal - is it possible to fit that with the differential in place or just more sensible to drop it out and do the job.

Thanks Paul

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On ‎10‎/‎20‎/‎2018 at 9:43 AM, pheaney said:

Regarding the recommendation on the oil seal - is it possible to fit that with the differential in place or just more sensible to drop it out and do the job.

Thanks Paul

Sorry about the delay in replying, I'm running a VPN here in Spain & notifications don't always get through. It might be possible if you have a nice 3 or 4 post lift & can get fully underneath but lying on your back under the car it will be a tall order. It is a PITA but you will make much better progress & do a much better job to drop the diff out & do it on the bench; there is a bloody great nut holding the prop shaft flange on that also has to come off to fit the seal. I used a smear of bearing Loctite on the outer edge of the seal for extra security. Also check the diff mounting pins as others have suggested as they could be  breaking up if they have not been previously reinforced.

Edited by Richard Crawley

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I've literally had something similar happen to me, was going to post a topic about it and noticed this thread. 

On mine I was just manoeuvring the car and all of a sudden when reversing I got a mechanical clunking with a slight resistance, not so bad moving forward, my first thought is the diff. Going to try and diagnose at the weekend.

Any tips in order to determine what's the cause? 

Gareth

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2 minutes ago, Mk2 Chopper said:

I've literally had something similar happen to me, was going to post a topic about it and noticed this thread. 

On mine I was just manoeuvring the car and all of a sudden when reversing I got a mechanical clunking with a slight resistance, not so bad moving forward, my first thought is the diff. Going to try and diagnose at the weekend.

Any tips in order to determine what's the cause? 

Gareth

Hi Gareth, that sounds like spline lock on one of the drive shafts but I could be wrong. Have you checked them for wear and grease?

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On ‎10‎/‎18‎/‎2018 at 5:22 PM, pheaney said:

 When taking off steadily  I get a rapid rapid hammering come graunching  from the rear o/s. Lapping round the local min-roundabout a few times slowly the noise is persistent .

This is the sound of a failing U-Joint. If you have the resources, replace all 6- then you know what you have.

Take the opportunity to drain your diff & refill with fresh hypoid gear oil. 

And, grease the axle splines.

 

Edited by Sapphire72

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6 hours ago, Kevo_6 said:

Hi Gareth, that sounds like spline lock on one of the drive shafts but I could be wrong. Have you checked them for wear and grease?

Not yet, but thanks for the suggestion, I'm planning to go under and try and feel for unwanted movement in the uj's, tightness of drive and prop shafts and then I thought maybe put the rear on axle stands and run it in reverse while listening if the initial checks don't throw anything up, the drive shafts don't look to be in the newest of condition so there maybe something in that. 

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The rear prop-shaft U-joint is often the first to fail.

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So just grab and push and pull each U joint to find if one or more is worn?

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Stick a long screwdriver, or such, in towards the center of each accessible u-j and wiggle it back-&-forth, while watching with a strong light and listen for unwanted noise.

What you want to see & feel is solidness, all parts of the U-J as one.

Wouldn't be a bad idea to have a grease/lube gun with you.

The outer U-J's of the axles are within the Trailing Arms.

Edited by Sapphire72

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edit time ran out...

To lube the outer axle U-J's you would have to remove the road wheel, brake drum, (6) nuts, wire/boot and pull outwards.

It's a job. Once it's done you should be good for a while.

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Brilliant, thanks for the pointers, will put it all to use at the weekend. 

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Hi I replace the o/s drive shaft with a spare  - the outer UJ was perhaps a little stiff but otherwise ok.  It wasn't too bad a job just tricky getting at the inner u/j bolts around the exhaust.

Anyway net result was no change - so I think the prop shaft UJ is the culprit after all.  

I had been in a bit of a rush for an event this weekend but had got the dates wrong so I think I will drop the diff as well and attempt to get the front seal replaced too. 

So best start with the parts order.

 

 

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If you are taking the diff out then plan your attack.

The diff is very heavy. 

I used ropes around the output flanges and the input flange.

These were lowered in turn until the diff could sit on the croc jack, where it could be lowered easily.

 

Roger

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From memory this is a Stag based idea to remove their diffs which are very similar, if you have a ropey old trolley jack it just needs a bracket welding up for it and bolting through the lift pad.  

Mick Richards

111.jpg

Edited by Motorsport Mickey

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post-5346-0-80960000-1387990665.jpg

Edited by 15eren
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This is for a TR6

Edited by 15eren

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If you are careful you can do it with a standard trolly jack. 

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